Many means are known for accelerating an object. Relatively small projectiles are efficiently accelerated via controlled explosive charges, such as with gunpowder. As the mass of the object being accelerated increases, however, the explosive force required greatly increases. For example, chemical combustion rockets are presently the only means that have been shown to be effective for launching payloads into space. Although much work has been done in attempting to develop alternative technologies for rapid acceleration of large payloads, such as electromagnetic launchers and plasma arc acceleration, no alternative technology to date has been proven useful and reliable, particularly in the launch of space vehicles.
In relation to space launch, while rocket propulsion is a long proven technology, reliance solely on rocket launch is problematic in that it remains expensive, dangerous, and is dominated by government funding. Such problems are illustrated by the retirement and lack of suitable replacement for the National Aeronautic and Space Administration's Space Shuttle program. The lead time for a new space launch using rocket propulsion is typically three to ten years. Space launches are infrequent, typically occurring less than once a year to a few times per year per customer. This has hampered advancements in certain technologies, such as communications. For example, satellite technologies have been slow and expensive to develop and are often outdated quickly after launch and satellite placement. These factors and attendant continued government involvement have locked in high costs and low profits. In particular, it is widely understood that present rocket launch technology can cost greater than $20,000 per kilogram of material for placement in an earth orbit.
Many types of gun launch systems have been proposed. A taxonomy of the various types is shown below.
All of the foregoing gun launch approaches share a common feature in that they impose unacceptably great acceleration forces on the payload. Accelerations are typically tens of thousands of G's. These impose enormous challenges in designing payloads that can survive the launch and still accomplish complex tasks after launch. Despite these challenges, perceived payoffs were so high that the US government invested hundreds of millions in R&D on all the various types of gun launchers in the 1970's through the early 1990's.
A few commercial entities have attempted to enter the space launch market; however efficient and reliable launch means are yet to be proven. Moreover, the persistently high costs of space launch mean government spending will continue to be an important factor in space launch technologies, and profitability will continue to remain low. Accordingly, there remains a need in the art for systems, methods, and apparatuses for reliable and efficient launch of projectiles, including space vehicles.